Hcg levels

Ok i need help maybe some clarification... my hcg levels in my 7th week according to my OB were great. I was in the ER for some bleeding which I’ve been spotting since finding out... every time i check, baby is great. Heart rate is great. But my hcg levels dropped from 60,233 to 54,483 but baby is growing and heart was beating 138 bpm that day. My cervix is long, and closed. Has this ever happened to anyone? My doctor says stay calm very hard btw but I’m trying he thinks things are ok but i retested today. I’ll be 8 weeks tomorrow where they don’t monitor the hcg levels as closely. I’m just looking for some positivity baby seems good but I’m just like is this normal i do not understand. With all the cramping and i believe normal spotting in the first trimester everything with baby has been good every time I’m checked but i just don’t understand this. Please help!